写入一个字符串，输出该字符串的所有排列组合。

C# code as below：

 

    class Program
    {
        static void Main(string[] args)
        {
            Method("123");
            Console.ReadKey();
        }

        static void Method(string str,string str2="")
        {
            if (str == null)
                return;

            if (str == string.Empty)
                Console.WriteLine(str2);

            for (int i = 0; i < str.Length; i++)
            {
                Method(str.Remove(i, 1), str2+str[i].ToString());
            }
        }
    }

 

output: